The present invention relates to a presser controller device of a carriage in a flat knitting machine.
A prior art presser controller of a carriage in a flat knitting machine is disclosed in Japanese Patent Laid-open Publication 2-14454 (1990). As shown in FIGS. 14 and 15, the carriage 30 has a stitch cam switching lever 31 which can swing during reverse movement of the carriage 30 with its swing member 32 traveling directly on a carriage rail 33. The stitch cam switching lever 31 is coupled to a cam plate 34 which carries a cam 36 provided close to one end thereof for actuation of an L-shaped link arm 37. The link arm cam 36 has a cam slot 35 arranged therein for accepting a cam follower 38 of the L-shaped link arm 37 so that when the stitch cam switching lever 31 performs a swing action, the L-shaped link arm 37 can move on a pivot. The L-shaped link arm 37 is linked at the other end by pivotal coupling to a cam lift-down plate actuator 39 which serves as a member of a presser controller device. The cam lift-down plate actuator 39 is arranged for pressing with its front end against a group of cam lift-down plates 42 from one end. There are provided springs 41 which are coupled at one end to a spring plate 40 fixedly mounted in place and at the other end to their respective cam lift-down plates 42. Each of the cam lift-down plates 42 has a notch 46 arranged in the upper edge thereof for engagement with an L-shaped stopper 45 which is coupled to a solenoid 44 located above each set of cams 43.
In operation, the movement of the cam plate 34 driven by the stitch cam switching lever 31 triggers the pivotal action of the L-shaped link arm 37 through the cam follower 38 moving along the cam slot 35 of the link arm cam 36. Accordingly, the cam lift-down plate actuator 39 moves forward against the yielding force of the springs 41, pressing out the cam lift-down plates 42. Then, desired ones of the solenoids 44 are energized for actuating their stoppers 45 to move into the notches 46 of the corresponding cam lift-down plates 42 so that the desired cams 43 can project outward.
However, such a prior art presser controller having the foregoing arrangement allows the cam lift-down actuator 39 to be driven by the action of the stitch cam switching lever 31 which may be affected by friction resistance between the swing member 32 and the carriage rail 33 thus causing a jerky movement of the cam plate 34. As the result, a constant, accurate operation of the presser control will rarely be executed.
Also, the prior art presser controller is easily affected by external factors and will thus operate without higher accuracy and consistency. This causes the operating solenoids 44, which have been selected and turned on for engagement of their stoppers 45 with the notches 46 of the corresponding cam lift-down plates 42, to remain energized constantly for ensuring the engagement. If the energization of the solenoids 44 is inactivated, the relevant cams 43 will retract into the carriage 30 upon the reverse movement of the carriage 30 manually actuated by an operator for replacement of a broken knitting needle with a new one.
For eliminating the foregoing drawbacks, the present invention has been invented through continuation of research and development. It is thus an object of the present invention to provide a presser controller device of a carriage in a flat knitting machine which contains an independent mechanism provided with a step motor for cam control so that desired cams can be actuated with more accuracy without using an intricate conventional system.